The ability to shock test disc drives allows disc drive manufacturers to improve the design of their disc drive systems, which, in most instances, improves the performance and stability of the disc drive during use and transport. Previously, only linear shock test systems existed.
Although the linear shock testers allowed the measurement of the amount of force required to break the disc drive, these testers nonetheless did not measure rotational shock tolerances of the disc drive elements. The amount of force imparted from a rotational shock that a disc drive, such as, for example, a hard disc drive ("HDD"), can withstand provides an indication as to the amount of force required to uncouple a latch mechanism of an actuator such that the actuator is displaced, or unparked, from its parking zone. If the actuator is displaced from the parking zone, the head, which is disposed at one end of the actuator, will adhere to the media in the data zone. The adherence of the head to the media is called stiction. If stiction occurs, the drive cannot be started again.
In an attempt to determine the amount of force imparted from rotational shock that a disc drive can sustain, rotational shock testers have been designed. In current designs, such as, for example, the designs by GHI Systems, the rotational shock tester induces rotational acceleration by a spring-latch, similar to a catapult. At least one problem with this design is that the center of rotation may not be coincide the desirable location on the test specimen, such as, for example, the spindle, the center of the pivot of the actuator arm or any location allowing the test specimen to be off-set.
Although the rotational shock testers allow for the measurement of rotational information, currently used shock testers are stand-alone testing systems and do not provide any information that allows an evaluation of the design of the disc drive system. A need in the industry exists for a rotational shock tester that allows for the measurement of rotational shock tolerances, and further, allows for an evaluation of the disc drive system such that the disc drive system can be designed to minimize susceptibility to rotational shock.